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4. DESCRIPTION OF THE OPM AND BWE TRIALS AND OPTIONS FOR FUTURE PEST MANAGEMENT The Optimum Pest Management (OPM) trial and the Boll Weevil Eradication (BWE) trial were both initiated in l978 to test in a relatively objective manner the scientific and technical advances made in the last two decades in controlling cotton insect pests. Both trials ended in l980. This chapter describes the major components of the field trials and alternate pest control strategies for use in the Cotton Belt. The reader is referred to the USDA reports listed in Appendix B for the detailed results of the field trials. THE OPM TRIAL The object of the OPM trial was to test the feasibility and effectiveness of an areawide cotton insect management program that would keep cotton insectsâparticularly the boll weevilâbelow the population levels at which they cause economic loss to cotton grow- ers. The trial was carried out over a three year period on over 30,000 acres of cotton in Panola County in northwestern Mississippi. The major components of the OPM trial were these: ⢠the use of traps baited with the pheromone grandlure to monitor the size and extent of the boll weevil population; ⢠urging cotton growers to plant cotton within certain recom- mended dates; ⢠providing recommendations to growers on when to apply pinhead square applications of insecticides, as determined by scouting of the cotton fields for boll weevils and other pests by commercial consultants, employees of grower associations, and extension service employees; ⢠full reimbursement of the costs incurred by growers who carried out the pinhead square applications of insecticides; 52
53 ⢠urging cotton growers to follow extension service recommenda- tions for in-season control of the boll weevil and other cotton insect pests; ⢠urging growers to destroy cotton plant stalks as soon as their cotton was harvested; ⢠full reimbursement of the costs incurred by growers who made insecticide applications at the end of the season to elimi- nate boll weevils entering diapause; and ⢠developing a system to verify both pinhead and diapause applications of insecticides before reimbursing cotton growers. In order to determine the success of the OPM trial in Panola County, the results of the trial there were compared with the results achieved through current insect control measures on a similar area in Pontotoc County, which lies to the east of Panola and is separated from it by Lafayette County. The OPM trial was appraised a biological and technical success by the USDA's Overall Evaluation Team (Economics and Statistics Service l98la) . They based their conclusions on two main points. ⢠Four late season applications of insecticide treatments used in l978 and l979 reduced numbers of boll weevils taken in traps during l979 and l980 by 78 and 94 percent, respec- tively, compared with trap catches in a Current Insect Control (CIC) area in Pontotoc County. There was no need for in-season application of insecticides for control of the boll weevil, and the number needed to control bollworms and bud- worms declined. ⢠A high percentage of the cotton acreage was included in fall diapause programs to eliminate areas for reinfestation. In l978, l979, and l980, cotton producers participated at the rate of 98.7 percent, 99.6 percent, and 99.7 percent, respectively. THE BWE TRIAL The object of the BWE trial was to test the feasibility of eradicating an established boll weevil population from a cotton- growing area in eastern North Carolina and Virginia that has been infested by the boll weevil since l922. The cotton acreage involved in the trial increased from about l5,500 acres in l978 to 32,500 acres in l980. An evaluation zone was established in the test area, extensive monitoring to determine the size and extent of the boll weevil population was carried out with pheromone traps, and a buffer zone surrounded the trial area.
54 In order to establish the proper state regulatory authority for the trial, and to establish procedures to measure cotton grower support for it, the legislatures of both North Carolina and Virginia enacted legislation entitled the Uniform Boll Weevil Eradication Act. Under authority of this legislation, each state established regulations to define the geographical area of the trial, to monitor and regulate the movement of certain articles in or through the trial area, to establish a system for recording the registered number of acres planted in cotton by cotton growers, and to permit the collec- tion of funds. Prior to the adoption of the final state regulations and the appropriation of state funds to pay for 25 percent of the cost of the trial, a statewide referendum of cotton growers was conducted to measure grower support for the trial. In December l976, growers in North Carolina affirmed, through a referendum, their approval for the trial to be conducted and to pay 50 percent of the costs. Approval for the trial in Virginia was obtained through a public hearing. The major components of the BWE trial carried out by APHIS were: ⢠the use of pheromone-baited traps located around every cotton field, ⢠in-season cotton pest control, ⢠diapause control following termination of cotton crop, ⢠defoliation or desiccation of all cotton to hasten harvest operations or to reduce the boll weevil food and breeding sites, ⢠sterile boll weevils distributed over entire cotton crop, and ⢠four foliar sprays of diflubenzuron in selected areas. The BWE trial was considered a biological as well as a technical success by USDA's Overall Evaluation Team (Economics and Statistics Service l98la). They based their conclusions on two main points. ⢠". . .no infestations of weevils were detected in the evalua- tion area between October l978 and September l980. . . . Review and analysis of relative data indicated that the boll weevils found in the evaluation area after June l979 were 'reintroduced1 weevils, therefore, 'native1 boll weevils were eradicated from the evaluation area." ⢠"Overall, in the North Carolina BWE trial, the average number of insecticide applications decreased in the evaluation area and in the associated Current Insect Control (CIC) area in North Carolina by 88 percent and 25 percent, respectively, as compared with the l974-l977 pretrial averages."
55 ALTERNATE PEST CONTROL STRATEGIES FOR USE IN THE COTTON BELT One option for dealing with cotton insect pests throughout the Cotton Belt in the future would be simply to continue to use current insect control (CIC). CIC includes all of the various practices discussed in Chapter 2âinsecticides, use of short-season varieties, use of cotton plants with natural host plant resistance to various insect pests, trap cropping, and so onâas they are used by individ- ual cotton growers. As time has gone on, however, CIC has tended to merge into so-called Integrated Pest Management, or IPM, programs. IPM programs vary among the states, but their general objective is to recommend and demonstrate to individual growers the economic advan- tages of scouting their fields for pests and following insect manage- ment practices recommended either by state cooperative extension services or grower cooperatives. IPM programs are voluntary efforts, and individual growers are free to deal with their pest problems as they see fit. It should be noted here that no comprehensive evaluation of the impact of CIC or of IPM programs on the environment has ever been attempted, and it would seem clear that an environmental assessment would be necessary as part of any attempt to assess the feasibility of alternative cotton insect control programs. In addition to CIC the usDA has listed several modifications of OPM and BWE programs for implementation beltwide. The definitions for these different beltwide boll weevil/insect management programs are given in Appendix A. OPM Options One OPM option that might be used in the future throughout the Cotton Belt would be essentially to use the OPM program tested in Mississippi throughout the belt. Such a program, whose principal thrust is to give cotton growers an incentive to comply by reimburs- ing them fully for the costs they incur in carrying out insecticide applications when recommended, is often referred to as OPM-I, or Optimum Pest Management with Incentives. Another OPM option is called Modified Optimum Pest Management (MOPM). MOPM would be used in areas where the application of insect- icides at the end of the season just prior to boll weevil diapause could not be implemented or appeared not to be needed. MOPM would use, if applicable, all the other practices tested in the Mississippi trial. Two other variations of OPM are called OPM-PI and OPM-NI. If the OPM-PI (Optimum Pest Management, Phased Incentives) program was chosen, the financial incentives to cotton growers would begin at l00 percent reimbursement of insecticide costs and would be reduced to zero over a period of four years. OPM-NI (Optimum Pest Management, No Incentives) would be just what that implies. Growers would receive no reimbursement for insecticide applications, but all the other elements of the Mississippi trial would be present, if applicable.
56 A final variation is called OPM-NI-BWE, or Optimum Pest Manage- ment with Boll Weevil Eradication. An OPM-NI-BWE program would last for four years, and the chief characteristics would be as follows: First year: cotton growers would be given information and education on cotton insect pest management and encouraged to follow recommended control practices. Second year: cotton growers would be responsible for in-season control of all insects, Including the boll weevil. USDA's APHIS would be responsible for releasing sterile boll weevils and beginning in early September (depending on the weather and the area), APHIS would carry out between 5 and l0 diapause insecticide applications, using recommended insecticides. Third year: APHIS would monitor and be responsible for control- ling boll weevil infestations, while cotton growers would be urged to follow recommended procedures to control other cotton insect pests. Fourth year (and subsequent years): MOPM practices would be carried out to control other cotton insect pests in a weevil-free environment; federal and state regulatory agencies would be responsi- ble for routine monitoring of weevil-free areas and control of incip- ient weevil infestations. The MOPM program would provide growers with information on how to control the cotton pests other than the boll weevil. The BWE Option The BWE option would be a beltwide program carried out by agen- cies of USDA and designed to eradicate the boll weevil from the United States. This eradication effort would begin in the eastern end of the Cotton Belt and proceed west through eight other zones over a period of three years. At the end of that period a buffer zone would be set up between the United States and Mexico to prevent reinfestation from that country. Pheromone traps would be used to detect any reinfestations of the boll weevil that required eradica- tion. The principal activities under the program would be as follows: First year: all applications of insecticides throughout the growing year would be carried out by APHIS, following state agency recommendations. Second year: APHIS would be responsible for all insecticide treatments intended to eradicate the boll weevil, and the distribu- tion of sterile male boll weevils over all lands planted in cotton; cotton growers themselves would be responsible for controlling all cotton insect pests other than the boll weevil, as well as for destroying cotton plant stalks after harvesting; growers would be urged to follow recommendations of cooperative extension services on dealing with other cotton insect pests. Third year: APHIS would be responsible for monitoring and controlling incipient boll weevil infestations; cotton growers would again be urged to carry out measures against other cotton insect pests as recommended by state agricultural extension services.
57 The use of pheromone traps during the beltwide eradication program would include: Pre-Implementation Survey. One trap per acre (a minimum of one per field) would be installed from about August to November. These traps would identify the potential severity of the weevil problem and pinpoint trouble spots. Diapause treatments would be initiated if the traps indicated that weevil populations were excessive. Use of Traps During Implementation. ⢠Spring trapping. One pheromone trap per acre would be placed at cotton fields of the previous season and would be oriented toward hibernation sites. The traps would be installed about one month before planting until cotton began to flower, a period of about three months during which newly planted fields would be located and mapped. Insecticide applications would be on an "as-needed" basis as shown by trap catches. ⢠In-season trapping. Following the spring trapping and insecticide applications, if needed, sterile males would be dropped for about 4 weeks at about the 6- to 8-leaf stage of growth. Traps would be reinstalled at the rate of one per acre, but this time they would be installed in-field. ⢠Fall trap survey. As cotton plants began to mature, phero- mone traps would again be installed around field borders. Trap catches would indicate the need for diapause insecticide applications. Post-Program Monitoring. If the traps indicated that the weevil population in an area had been eliminated, the area would be assigned to the monitoring unit on about July l. Traps would be installed in the spring for three months around cotton fields of the previous season and in the fall for three months around current cotton fields. During the monitoring period the trap densities would be: ⢠First year: one per l0 acres ⢠Second year: one per 50 acres ⢠Third year: one per 200 acres If boll weevils were captured at any time during this period, trap density would be increased to one per acre in a zone of one to two miles around the detection point or area.
